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Note that this observational study found that gastric bypass surgery was associated with reduced mortality compared to no surgery across almost all age groups.

Be aware that the control group was obtained from driver's license records; access to healthcare may be a significant confounder here.

Older obese patients undergoing bariatric surgery got about the same long-term mortality benefit as younger patients, according to a study in JAMA Surgery.

At a mean 7 years of follow-up, severely obese patients ages 55-74 were 50% less likely to die from any cause compared with matched controls not undergoing surgery. The risk reduction was 43% for surgery patients ages 45-54 and 54% for those 35-44, reported a research team led by Lance Davidson, PhD, of Brigham Young University in Provo, Utah.

However, Davidson and colleagues found no mortality benefit for bariatric surgery patients younger than 35. This lack of mortality benefit was driven by a significantly higher rate of externally caused deaths in this age group, primarily among women. Externally caused deaths included deaths from suicide, homicide, and undetermined or unintentional injuries.

"We hypothesized that undergoing gastric bypass surgery at older ages might reduce the effectiveness of the operation owing to long-standing disease that would be harder to reverse after weight loss. However, it appears that severely obese persons aged 55 through 74 years who undergo gastric bypass surgery are likely to have significantly reduced long-term mortality compared with age-matched individuals not undergoing surgery," Davidson and colleagues wrote.

The study included 7,925 severely obese patients undergoing Roux-en-Y gastric bypass surgery at a private surgical practice from 1984 through 2002. Their mean age was 39.5 and mean body mass index (BMI) was 45.3 at the time of surgery. These patients were matched in terms of age, sex, and BMI with 7,925 severely obese control individuals not undergoing gastric bypass, found in Utah driver's license records.

Davidson and colleagues divided the surgery patients into four age categories: younger than 35, 35-44, 45-54, and 54-75. The investigators compared rates of all-cause and cause-specific mortality in these groups with their matched controls for up to 18 years.

During follow-up (mean 7.2 years), there were 213 deaths in the surgery group and 321 deaths in the control group.

Compared to the controls, adjusted all-cause mortality risk was significantly lower in the surgery patients 35-44 years old (hazard ratio 0.54; 95% CI 0.38-0.77), 45-54 years old (HR 0.43; 95% CI 0.30-0.62), and 55-74 years old (HR 0.50; 95% CI 0.31-0.79) (P<0.003 for all). In all age groups, the risk of death from cardiovascular disease and cancer was significantly lower.

However, all-cause mortality was not significantly lower in the surgery patients younger than 35 (HR 1.22; 95% CI 0.82-1.81; P=0.34).

Davidson and colleagues found that the lack of mortality benefit in this age group was due to a greater risk for externally caused deaths (HR 2.53; 95% CI 1.27-5.07; P=0.009). Further analysis revealed the risk of externally caused death was significantly higher for women in this age group (HR 3.08; 95% CI 1.4-6.7; P=0.005) but not for men (HR 0.98; 95% CI 0.2-4.8; P=0.98).

Previous studies suggested that patients presenting for bariatric surgery are already at a greater risk for psychiatric disorders and substance abuse, Davidson and colleagues noted. "In addition to the increased risk for substance use disorders, postsurgical dissatisfaction related to presurgical expectations may exist. Clearly, additional research related to the behavioral and psychological aspects before and after bariatric surgery, perhaps especially in the younger population, is warranted," they said.

As for their overall study results, Davidson and colleagues wrote, "Although gastric bypass surgery appears to be effective when performed in individuals at any age, these results do not imply that a severely obese person should wait until an older age to undergo surgery. A prior study found that the risk of complications early after surgery increases with age."

The study "is a powerful argument for keeping bariatric surgery in the armamentarium for treating obesity in older individuals," said Malcolm Robinson, MD, of Harvard Medical School in Boston, in an editorial.

"However," Robinson cautioned, "one should be judicious in the workup, selection, and postoperative support of both young and old patients before offering this powerful tool for treating obesity."

In addition, "The current study suggests that young women in particular are a vulnerable population who may need additional preoperative preparation and postoperative follow-up to limit potentially avoidable causes of death," Robinson said.

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